BIOFILMS IN BIOENERGETICS AND ECOBIOTECHNOLOGY: RESEARCH HISTORY AND APPLICATION PERSPECTIVES

Abstract

The historical paradigm shift from studying planktonic bacteria to understanding the protective extracellular polymeric substance (EPS) matrix has fundamentally transformed environmental biotechnology. Once considered operational impediments, biofilms are now recognized as highly organized microbial consortia and essential tools for advanced wastewater treatment, bioremediation, and sustainable bioenergy production. Aim. The study aimed to analyze the evolution of knowledge regarding biofilms - from early observations to their contemporary role in bioelectrochemical systems and nitrification - thereby outlining future perspectives for the application of microbial communities. Materials and Methods. A comprehensive theoretical synthesis of contemporary literature was conducted, focusing on EPS matrix dynamics, spatial stratification in granular and membrane bioreactors, and direct interspecies electron transfer (DIET). The analysis encompasses structural data on methanogenic archaea, exoelectrogens (e.g., Geobacter), and rhizosphere biofilms within constructed wetland-microbial fuel cells (CW-MFCs). Results. Biofilm engineering exploited spatial substrate gradients to facilitate syntrophic metabolism, significantly improving nitrogen removal via ANAMMOX processes and maximizing methane yields. The EPS matrix functions both as a chemical buffer against toxic stress and a conductive scaffold. In bioelectrochemical systems, c-type cytochromes and flavins facilitate efficient long-range electron transfer. Furthermore, biofilm-mediated horizontal gene transfer and quorum-sensing manipulation enhance the biodegradation of recalcitrant xenobiotics, heavy metal biomineralization, and plastic depolymerization. Conclusions. Transitioning to the targeted engineering of biofilm architecture using synthetic ecology principles significantly intensified environmental resource recovery. Managing the EPS matrix transforms conventional biological treatment into robust, self-regulating biotechnological systems capable of continuous, sustainable energy generation under fluctuating environmental conditions.